Video projector colour wheels query

[N_Cook]

Why is the red sector a denser colour than the blue or green sectors, or at
least on 2 makes I've looked at, or would more objective/scientific analysis
show the same colour density?
It seems to mean that if the lamp becomes under-powered or dirty integrator/
light tunnel etc then the reds become brown or plum , unless projected onto
a small screen area

 

[William Sommerwerck]

"N_Cook" wrote in message

Why is the red sector a denser colour than the blue or green sectors,
or at least on 2 makes I've looked at, or would more objective/scientific
analysis show the same colour density?

Why should they be identical to the eye? The eye is less sensitive to red and
blue than green. And red and blue wavelengths cover a narrower part of the
spectrum than green, so less visible light gets through.

http://thelawlers.com/Blognosticator/?p=104

http://photo.net/filters-bags-tripods-accessories-forum/00WUUM

 

[N_Cook]

"N_Cook" wrote in message

Why should they be identical to the eye? The eye is less sensitive to red and
blue than green. And red and blue wavelengths cover a narrower part of the
spectrum than green, so less visible light gets through.

http://thelawlers.com/Blognosticator/?p=104

http://photo.net/filters-bags-tripods-accessories-forum/00WUUM

For both makes, completely different sizes etc, the transmissivity , by eye,
of the blue sector matches the green sector .
This projector is used for graphical displays and red indistinguishable from
black at the usual diagonal is a problem. Cleaning the UV filter at the C/W
and cleaning the surfaces of the integrator tunnel has improved things a bit
but not enough. Orange or pink would probably be alright for this use
instead of red but dark brown or dark plum is not.
I just tried a scrapped dichroic C/W and it is quite easy to scrape lines in
the coating , say 10 percent , to pass something more like an orange colour.
Anyone ever done this to get round underpowered lamp problem and red/brown
issue? Would heat build up from the multiple scratches compared to just the
3 butt joins of the glass sectors , as made
Why dichroic for primary colours transmission and reflection of the
complement. In dichroic lamp reflectiors I can see a point in that it
reflects the visible light and transmits the heat through the glass to be
delt with by fans.
I cannot see that reflecting the complement is a by-product of reflecting IR
or UV back to the lamp.

 

[N_Cook]

Instead of destroying NASA tech, I decided to open up the hole in the mask
between lamp and C/W, to see if getting more light will help, even if off
principal axis. At least I can put a mask back if there is too much colour
spill over from adjascent sectors, a more extreme version of adjusting the
C/W delay . That did not work because if red is brown then brown does not
become pinker by losing some red and gaining some blue from the sector on
that side or going orange by losing some red and gaining some green from
the other adjascent sector